Researchers Create Light-Based Way of Printing Nano-Sized Structures

Researchers at the Georgia Institute of Technology have developed a new light-based way of printing nano-sized structures that is significantly cheaper and faster than current technology. This discovery has the potential to bring new technologies from labs into larger production. 
 
Assistant professor Sourabh Saha and Ph.D. student Jungho Choi at the Gerorge W. Woodruff School of Mechanical Engineering have developed the technique that prints metal nanostructures that is 480 time faster and 35 times cheaper than the current method.
 
The findings have been published in the Advanced Materials journal. Saha and Choi’s scalable solutions could transform current technologies that are expensive and slow. 
 
The development of electronic devices, sensors, solar energy conversion and other systems are reliant on nanopatterning, which creates unique structures that are printed on metal at the nanoscale. This technique uses high-intensity light sources, a femtosecond laser that can cost up to half a million dollars. 
 
Saha and Choi searched for a low-cost, low-intensity light that acts similar to femtosecond laser but is more affordable. They chose super luminescent light-emitting diodes (SLEDs) that emit light a billion times less intense than femtosecond lasers and are much more commercially available. 
 
“As a scientific community, we don’t have the ability to make enough of these nanomaterials quickly and affordably, and that is why promising technologies often stay limited to the lab and don’t get translated into real-world applications,” Saha explained. 
 
The pair created an original projection-style printing technology that converts digital images into optical images and displays them on a glass surface. Although operating like digital projectors, the system produces images that are more sharply focused. They were able to leverage the unique properties of the super luminescent light to generate sharp images with minimal defects. 
 
Then they developed a clear ink solution that could absorb light with metal salt and other chemicals. When light from the projection system hit the light, a chemical reaction occurred that converted the salt solution into metal. Metal nanoparticles stuck to the surface of the glass and the agglomeration of the metal particles created the nanostructure. 
 
Due to the projection type of printing, this system can print an entire structure in one go, rather than point by point. Saha and Choi say their technique will be useful for people working in fields that require a variety of complex metallic nanostructures like electronics, plasmonic, and optics.
 
“At the present, only top universities have access to these expensive technologies, and even then, they are located in shared facilities and are not always available. We want to democratize the capability of nanoscale 3D printing, and we hope our research opens the door for greater access to this type of process at a low cost,” said Choi. 
 
The technique was also tested with low-intensity light, however, it only proved successful if the images were sharply focused. Saha and Choi believe that their work can be replicated by researchers using commercially available hardware. The type of SLED used in their printer cost about $3,000. 
 
“I think the metrics of cost and speed have been greatly undervalued in the scientific community that works on fabrication and manufacturing of tiny structures,” Saha said. “In the real world, these metrics are important when it comes to translating discoveries from the lab to industry. Only when we have manufacturing techniques that take these metrics into account will we be able to fully leverage nanotechnology for societal benefit.”